Investigation of the Combined Effects of External Mass Transfer and Biodegradation Rates on Phenol Removal Using Immobilized P. putida in a Packed-Bed Column Reactor

Abstract

A quantitative analysis of external mass transfer combined with a biodegradation reaction and correlation of the experiment with theory was performed for phenol removal using calcium-alginate gel-immobilized P. putida in a packed-bed column reactor. Assuming first-order biodegradation kinetics, pseudo first-order biodegradation rate constants ( k p) were calculated. To investigate the effect of external film diffusion on the biodegradation rate, various mass transfer correlation models of the type j D = KN Re −(1−n) were systematically tested and the mass transfer coefficients ( k m ) were calculated as a function of the mass flux (G) and the Reynolds number ( N Re) at different n values. The intrinsic first-order biodegradation rate constants ( k) and the surface areas per unit weight of dried cells for mass transfer ( A m) were determined from 1/ k p vs. 1/ G n plots at the same n values. Finally, combining the k values with k m A m values, the pseudo first-order biodegradation rate constants ( k p) were calculated again and compared with the k p values determined from experimental data; thus, it was decided that the mass transfer correlation j D = 1.625 Re −0.507 accurately predicted our experimental data.